From 5b9d8a838f681baaf32564b9586e885e469659c7 Mon Sep 17 00:00:00 2001
From: Jakob Borg <jakob@kastelo.net>
Date: Sun, 15 Sep 2024 17:00:32 +0200
Subject: [PATCH] chore(stdiscosrv): ensure incoming addresses are sorted and
 unique

---
 cmd/stdiscosrv/apisrv.go   | 9 +++++----
 cmd/stdiscosrv/database.go | 5 +++++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/cmd/stdiscosrv/apisrv.go b/cmd/stdiscosrv/apisrv.go
index fced38e09..96bfce75c 100644
--- a/cmd/stdiscosrv/apisrv.go
+++ b/cmd/stdiscosrv/apisrv.go
@@ -307,16 +307,17 @@ func (s *apiSrv) handleAnnounce(deviceID protocol.DeviceID, addresses []string)
 	now := time.Now()
 	expire := now.Add(addressExpiryTime).UnixNano()
 
+	// The address slice must always be sorted for database merges to work
+	// properly.
+	slices.Sort(addresses)
+	addresses = slices.Compact(addresses)
+
 	dbAddrs := make([]DatabaseAddress, len(addresses))
 	for i := range addresses {
 		dbAddrs[i].Address = addresses[i]
 		dbAddrs[i].Expires = expire
 	}
 
-	// The address slice must always be sorted for database merges to work
-	// properly.
-	slices.SortFunc(dbAddrs, DatabaseAddress.Cmp)
-
 	seen := now.UnixNano()
 	if s.repl != nil {
 		s.repl.send(&deviceID, dbAddrs, seen)
diff --git a/cmd/stdiscosrv/database.go b/cmd/stdiscosrv/database.go
index 4f2379c58..2a796848a 100644
--- a/cmd/stdiscosrv/database.go
+++ b/cmd/stdiscosrv/database.go
@@ -350,6 +350,7 @@ func (s *inMemoryStore) read() (int, error) {
 		}
 
 		slices.SortFunc(rec.Addresses, DatabaseAddress.Cmp)
+		rec.Addresses = slices.CompactFunc(rec.Addresses, DatabaseAddress.Equal)
 		s.m.Store(key, DatabaseRecord{
 			Addresses: expire(rec.Addresses, s.clock.Now()),
 			Seen:      rec.Seen,
@@ -420,3 +421,7 @@ func (d DatabaseAddress) Cmp(other DatabaseAddress) (n int) {
 	}
 	return cmp.Compare(d.Expires, other.Expires)
 }
+
+func (d DatabaseAddress) Equal(other DatabaseAddress) bool {
+	return d.Address == other.Address
+}